Manufacture of hydrocarbon products by hydrogenation of carbon oxides



Patented July 23, 1940 sauna MANUFACTURE OF OXIDES ROCABBON PROD- UGTSBY HYDROGINA'I'ION OI CARBON William a. cattle, mum, at. 1., as... to

. Standard-I. G. Company No Drawing. Application January 11,1036,

Serial No. some '3 Claims. (01. 260-449) This invention relates toimprovements in the manufacture of valuable hydrocarbon products by thehydrogenation of carbon oxides. A particular object of the invention isto provide for I better operation of the process by pressure controlapplied with respect. to the reacting compo-- -nents so that theirpartial pressures may be held within the optimum range.

A further object of the invention is to control 10 the progress of thereaction by regulating the addition or withdrawal of inert gas and/orreacting gases.

It is known from U. S. Patent 1,201,8 0, granted October 1'7, 1916, thatoxygenated compounds and hydrocarbons can be obtained by reacting carbonoxides with hydrogen in the presence of catalysts at high temperatureand pressure. Inert gases may be present in this process, as describedin United States Patent 1,788,170, granted Janu ary 6, 1931. It isfurther known from the Eischer-Tropsch synthesis as described in U. S.Patent 1,746,464, granted February 11, 1930, that hydrocarbon productsmay be obtained by hydrogenating carbon oxides under lower pressure andI temperature. a

The present invention is distinguished from these prior processes by thefact that the synthesis of hydrocarbons from carbon oxides is con- 1ducted under higher pressure (in excess of 5 at- 39 mospheres absolute)while retaining the combined partial pressure of the reacting componentsat a value less than 5 atmospheres. In this way the tendency to formoxygen-containing compounds, encountered at high pressure withrelatively una diluted gases, is avoided; At the same time the catalystis protected by the inert gases from the adverse e'fiect of excessiveheat which may develop when relatively undiluted gases are used. Theinert gases, either present initially or introduced in the course of thereaction, disperse the heat of reaction. The yield per pass ofhydrocarbon products for each volume of gas treated is naturally less bythe present method, due to the presence '0! adiluent, but the vunreactedcom- 5 ponents are recycled so asto secure ultimately the same or abetter conversion than with the undiluted gases. 4 It is preferred toutilize a water gas ---:--x of the approximate composition 50% carbonmen 59 oxide and 50% hydrogen and to dilute this with nitrogen orotherinert gas such as methane or ethane. If the reaction is to be, conductedat atmospheres absolute pressure then the vol= ume of diluent should besomewhat more than 55 the combined volume of thereactants, it a totalpressure of atmospheres is used the volume of diluent should be at leastthree times the combined volume 0! the reactants. Under the aboveconditions the partial pressure of the reactants will be below 5atmospheres in each case and the 5 products will be hydrocarbon incharacter.

More specifically, one part of thecarbon monoxide-hydrogen mixture maybe used for each 1% to 4 parts of the inert diluent. The catalyst may beany of those described in Patent No. 1,74 ,4 10 or other catalysts whichare available for the synthesis of hydrocarbons from carbon oxides. Thetemperature is advantageously somewhat higher than described in Patent1,746,464 and ranges between about 380 to 450 C. The higher 16temperature expedites the reaction but lower temperatures may be used.

The gas mixture is passed through or over the catalyst at a rate of10-20 litres per hour and provision is preferably made for introducingaddiso tional streams of inert gas and/or reacting gases, or forwithdrawing one or more of these, in order to control the reaction.

The process is preferably run to produce hydrocarbons lying mostly inthe gasoline range and adapted for motor fuel, as such or after blendingwith benzol, polymer gasoline, cracked gasoline, or other suitableblending'material.

Benzol may be produced as an incident of the process by adjusting theconditions (especially. by elevating the temperature) to producesubstantial quantities of methane, as well as higher hydrocarbons, andtreating the methane with an electricalv spark discharge in known mannerto produce acetylene which is then polymerized to 5 benzol by means ofan iron-nickel-silica gel catalyst at about 250-260 C. An alternativeknown process for this purpose is the pyrolysis of meth-= ane at1000-1300" C. without substantial pressure and in the absence ofcatalysts, to form, finely divided carbon, light liquid hydrocarbons.(mostly benzol with small quantities of naphthenes) and hydrogen.

Various other pressures and temperatures might be used but in all casesthe partial pres-' sure of the carbon monoxirl and hydrogen togethershould be below 5 atmospheres.

ll claim:

1. Process of making hydrocarbons from carbon oxides by hydrogenationcomprising'subject- 60 ing a mixture of an oxide of carbon and hydrogen.to the action of a Fischer 'irops'ch catalyst at" temperatures betweenabout 380 and450 C. and at a total pressure between 10 and 20atmospheres but in the presence of a suflicient volume of a.

User. i Mi diluting gas to insure a partial pressure "of the combinedreactants below 5 atmospheres.

2. The process of makinghydrocarbons from carbon oxides by hydrogenationunder pressures between 10 and 20 atmospheresand at a temperaturebetween about 380 and 450 csin the presence of a. Fischer-Tropschcatalyst; compris-v ing diluting the reacting gases with 1% to} volumesof inert gas per volume of reacting gases pheres.

1 3..Process according to claim 1 in which the relative volumes of theindividual gases present 5 during the reaction are varied to control thereaction.

WILLIAM E.

